A notorious infrastructure company’s largesse towards NSW Liberals translated to “gold-edged service” including a favourable press release from a shadow minister, a corruption inquiry has heard.

The Independent Commission Against Corruption (ICAC) is investigating suspect political donations that allegedly flowed through a slush fund founded by Tim Koelma, an ex-staffer to former NSW minister Chris Hartcher.

Australian Water Holdings (AWH) is alleged to have paid $183,000 to the “sham” company, EightByFive.

Former AWH boss Nick Di Girolamo on Friday was shown emails and phone records suggesting he had input into a media release that was sent out by Mr Hartcher in 2010, when he was a shadow minister, and which urged further development of greenfield sites in Sydney’s northwest.

At the time, AWH was pushing for a $1 billion public-private partnership to provide water infrastructure in the region.

“Very good media release,” Mr Di Girolamo wrote after Mr Koelma showed him the release.

The inquiry heard Mr Hartcher put questions on notice to parliament that asked whether Sydney Water’s general manager “may be providing preferential commercial arrangements for a significant contractor”.

“That is gold-edged service that you’re getting, isn’t it?” junior counsel assisting Greg O’Mahoney said to Mr Di Girolamo.

The parliamentary questions came as AWH was locked in a commercial dispute with Sydney Water.

At the time, Mr Koelma allegedly arranged for false anonymous corruption allegations against senior Sydney Water executives Ron Quill and Kerry Schott to be sent to the ICAC.

But Mr Di Girolamo denied his company had received any preferential treatment.

“Regardless of what political donations I made, regardless of the EightByFive retainer, I don’t believe I ever received any preferential or any biased favours from, at this point in time the opposition, nor from the government, when it came into parliament,” he said.

“You were getting the service you were from this political office in the context of Mr Koelma dealing with it extensively,” Mr O’Mahoney said.

“The reason he was dealing with it extensively was wholly and solely because of the payments that you were making to EightByFive.”

“I don’t accept that,” Mr Di Girolamo said.

He is due back in the witness box on Monday.